english title

One important parameter to specify in nuclear fuels is the oxygen-metal ratio, many tests were described in literature to determine it. Gravimetric methods are possibly the most used and usually a good precision was obtained analyzing sintered materials. However this method is affected by the humidity and impurities sorbed in the samples, especially in powders. The spectrophotometric methods determine oxygen-uranium ratio by measuring the absorbance of different ionic species in phosphoric acid. This technique is simply and is not affected by humidity and impurities. Owing to discrepancy in the results between both methods, it was carried out in our laboratory, a study on various gravimetric and spectrophotometric methods. Several assays and analysis were performed comparing test procedures, trying to obtain better precision and accuracy. This work presents the results obtained and the recommended procedure to use with sintered and unsintered materials. (author)